Pyridazinones have shown a broad-spectrum biological activity, e.g. as an antidepressant, a vasodilatator, a cardiotonic, an acesodyne/anti-inflammatory agent or an antihypertensive, as acaricide or herbicide in agriculture, and also as inhibitors for acetylcholine esterase, aldose reductase, monoamine oxidase, CDKs, COX-2 and P38MAP kinase, etc. Some pyridazinones have exhibited an antitumor activity to a certain extent. US2007/0072866 A1 reported a series of pyridazinones having a structure formula of:
as a GSK-3β inhibitor, which can be used for treating metabolic diseases, neurodegenerative diseases or other related diseases or disorders. CN200380105057 further defines that A is C(O)NHR or NHC(O)R; while in US2007/0072866A1, A is defined as a heterocyclic substituent.
WO 03/059891 and WO 2005/007632 disclose that pyridazinones are useful for treating diseases or conditions caused or exacerbated by unregulated P38 MAP kinase and/or TNF activity. In the above patent literatures, the pyridazinones have a structure formula of:
and are useful for treating inflammatory diseases, diabetes, Alzheimer's disease or cancer. Although the described pyridazinones covers almost all substituents, actually, R4 is mainly aryl, R1 is mainly halogen, R2 is various kinds of substituents, and R3 is only H.
The most related literatures of the present application are the patent literatures concerning antitumor activities filed by Aventis Co. under WO2004/046130, WO2005085231, WO2005/111019 and US2007/0173503, which involve a kind of pyridazinone derivatives of formula
as inhibitors of CDK2, wherein, X is C(O)NHR, NHC(O)R or a heterocycle containing N, R2 is H, and R3 is an aromatic ring or heterocycle.
In addition, pyridazinones are described as inhibitors of RAF kinase in WO2006/124874 for treating tumors, and as inhibitors against tumors in European patent publication 0665223. However, such pyridazinones are totally different from the compounds of the present application.
Moreover, various other pyridazinone derivatives are disclosed in other literatures, and they are different from those in the present application in the selection of substituted groups, moieties and/or 6-positioned aromatic ring groups, or in applications of the compounds.
It is well known that liver cancer is the 5th frequent tumor diseases in males, and the 8th frequent tumor diseases in females. In 2007, it was estimated that 80% patients suffered newly from liver cancer were in developing countries, and 55% of all new patients were in China. In developing countries, among the liver cancer patients, 59% were attributed to HBV, and 33% were attributed to HCV. Particularly, there exists a great market demands for drugs against liver cancer due to the severe HBV infection and increasing incidence of liver cancer in Asia-Pacific countries.